It is often necessary in medically treating a patient to establish long term vascular access to a specific desired interior body site for purposes of administering liquid therapeutic agents and/or for removing bodily fluids for testing/monitoring, for treatment before being returned to the body, or for disposal. In another increasingly common medical procedure, it is desired to deliver a contained heat exchange fluid at a temperature above or below normal body temperature to a specific interior body site for providing localized or general heating or cooling. In still other common medical procedures, such as angioplasty and laparoscopy, medical instrumentation is guided through a pre-positioned catheter line to a particular internal body location to monitor body conditions and/or to perform medical/surgical procedures.
Particularly in the case of administering fluids to, or removing fluids from, the body continuously or periodically over an extended time period, it is known in the medical arts to use what are known as “permanent” catheterization techniques employing subcutaneous-implanted devices such as tunneled central venous catheters (CVCs) for durations ranging from a few weeks to years. Examples of such subcutaneous-implanted and related medical devices are found in U.S. Pat. No. 4,266,999 (Baier); U.S. Pat. No. 4,405,305 (Stephen et al.); U.S. Pat. No. 4,488,877 (Klein et al.); U.S. Pat. No. 4,668,222 (Poirier); U.S. Pat. No. 4,897,081 (Poirier et al.); U.S. Pat. No. 4,935,004 (Cruz); U.S. Pat. No. 5,098,397 (Svensson et al.); U.S. Pat. No. 5,100,392 (Orth et al.); U.S. Pat. No. 5,242,415 (Kantrowitz et al.); U.S. Pat. No. 5,662,616 (Bousquet); U.S. Pat. No. 5,823,994 (Sharkey et al.); U.S. Pat. No. 5,830,184 (Basta); U.S. Pat. No. 5,848,987 (Baudino et al.); U.S. Pat. No. 5,882,341 (Bousquet); U.S. Pat. No. 5,989,213 (Maginot); and U.S. Pat. No. 6,033,382 (Basta), each of which is incorporated herein by reference. Examples of therapeutic regimens requiring such long term continuous or periodic access to a specific internal body location include parenteral feeding, chemotherapy, antibiotic administration, dialysis, and others.
Generally, the length of time the patient will be catheterized dictates whether a physician will utilize a “temporary” catheterization technique (i.e., a technique in which the catheter is left in a blood vessel for a relatively short period of time such as a few minutes, hours, days, or weeks) or a “permanent” catheterization technique (i.e., a technique in which the catheter is left in a blood vessel for a relatively long period of time such a several months or indefinitely).
For example, a procedure in which a clot is aspirated from a blood vessel typically includes placing the catheter in the blood vessel for a relatively short period of time such as a few minutes to a few hours and then withdrawing the catheter once the clot has been removed. Therefore, when performing such an aspiration procedure, it is common for a physician to use the temporary catheterization technique to place the catheter in the blood vessel of the patient.
On the other hand, when a procedure is performed to effect hemodialysis, a physician may place a catheter in the blood vessel for a relatively long period of time. In particular, a patient suffering from kidney failure who is involved in a hemodialysis regimen typically requires a dialysis session three times per week for an indefinite period of time whereby extra fluid, chemicals, and wastes are removed from his/her body. A patient who is involved in such a hemodialysis regimen may need a catheter placed in his/her blood vessel for a relatively long period of time in order to provide a ready means for vascular access into his/her bloodstream over such relatively long period of time. See, for example, K. Atherikul et al., “Adequacy of Haemodialysis with Cuffed Central-Vein Catheters,” in Nephrology Dialysis Transplantation (vol. 13, no. 3, March 1998), which article is incorporated herein by reference. This long term placement of the catheter for dialysis purposes may be desirable for a number of reasons.
First, a patient may have experienced progressive loss of other conventional long term vascular access possibilities such as surgically created arteriovenous fistulas. Accordingly, the long term placement of the catheter in the patient's blood vessel may be the best, or only, alternative for the patient as he/she proceeds with the hemodialysis regimen.
Additionally, the long term placement of the catheter in the patient's blood vessel may be desirable after initial creation of an arteriovenous fistula in the patient's body. In particular, it is desirable to provide a ready means for vascular access into the patient's bloodstream during a maturation period of the arteriovenous fistula. The maturation period allows the arteriovenous fistula to develop sufficiently so that it will function as a ready means for vascular access into the patient's bloodstream which may be safely punctured multiple times per week for hemodialysis. The length of time of this maturation period is typically on the order of several weeks (e.g., three weeks) to many months (e.g., six months). Therefore, when performing a hemodialysis procedure, it is common for a physician to use the permanent catheterization technique to place the catheter in the blood vessel of the patient.
These two catheterization techniques are significantly different with respect to their complexity and degree of invasiveness. For example, in the case of the temporary catheterization technique, it is common to insert a temporary catheter into a patient's blood vessel using a “direct puncture technique.” This technique entails creating a small incision in a patient's skin with a scalpel directly over the blood vessel to be catheterized. A needle is then advanced through the skin incision and subcutaneous tissue and into the blood vessel. Thereafter, a guidewire is advanced through the needle into the blood vessel and the needle is subsequently removed over the guidewire. Then, one or more tubular vessel dilators are used to widen the opening defined in the skin and subcutaneous tissue, and further to widen the opening defined in the blood vessel wall to a caliber similar to that of the temporary catheter. The temporary catheter is then advanced over the guidewire and into the blood vessel. Thereafter, the guidewire can be removed.
When the temporary catheterization technique is used, for example, during a clot aspiration procedure, two catheters are usually placed in the blood vessel of a patient. In particular, an outer catheter is usually placed within the blood vessel using the above described direct puncture technique so that its distal opening is located near the clot. Thereafter, an inner catheter having a smaller caliber relative to the outer catheter is advanced through a lumen of the outer catheter. While the inner catheter is positioned within the outer catheter, an aspiration vacuum is applied to the inner catheter with a syringe. If the size of the clot (or fragments thereof) are smaller than the inner diameter of the inner catheter, then the clot or clot fragments are drawn into and through the inner catheter thereby removing the clot from the blood vessel. If the size of the clot or clot fragments are larger than the inner diameter of the inner catheter, then the clot or clot fragments are drawn to a location adjacent to the distal orifice of the inner catheter. Subsequently, while the aspiration vacuum is still being applied, the inner catheter is withdrawn from the outer catheter thereby additionally withdrawing the larger clot or clot fragments from the outer catheter and the patient's blood vessel. Thereafter, the outer catheter remains temporarily in place within the blood vessel of the patient for subsequent injections of radiographic contrast for imaging purposes to determine the extent of clot remaining in the blood vessel as well as to determine if clot has migrated to another location within the blood vessel. The outer catheter, which remains temporarily in place in the blood vessel, provides a conduit for the inner catheter to be advanced back into the patient's blood vessel for additional aspiration attempts which are usually required for complete removal of the clot from the blood vessel.
If an outer catheter needs to be replaced during a clot aspiration procedure because of catheter malfunction, such replacement can be accomplished by advancing a guidewire through the lumen of the outer catheter and into the blood vessel. The existing outer catheter can then be removed over the guidewire to a location outside of the patient's body. Thereafter, a new outer catheter is placed in the patient's blood vessel by advancing the new outer catheter over the guidewire as discussed above.
In contrast to the temporary catheterization techniques, the permanent catheterization techniques typically entail inserting a “permanent” catheter into a patient's blood vessel using a “tunneled catheter technique.” The tunneled catheter technique includes: (i) creating a first opening by making a small incision in a patient's skin with a scalpel directly over the blood vessel to be catheterized; (ii) puncturing the blood vessel at a location directly below the first opening by advancing a needle through the skin incision and subcutaneous tissue and into the blood vessel; (iii) advancing a guidewire through the needle into the blood vessel; (iv) removing the needle over the guidewire; (v) passing one or more tubular vessel dilators over the guidewire to widen the opening defined in the skin and subcutaneous tissue, and further to widen the opening defined in the blood vessel wall to a caliber similar to that of the tubular guide; (vi) advancing the tubular guide, or introducer sheath, over the guidewire and into the blood vessel; (vii) thereafter, creating a second opening in the patient's skin spaced apart at least several centimeters from the first opening; (viii) advancing a tunneling instrument from the second opening to the first opening so as to create a passageway, or tunnel, within the subcutaneous tissue under the skin between the first opening and the second opening; (ix) advancing a permanent catheter having a tissue ingrowth member attached to an outer surface thereof into the second opening and through the passageway such that a distal end of the permanent catheter is located adjacent the first opening; (x) inserting the distal end of the permanent catheter through the tubular guide member and into the blood vessel to be catheterized whereby the tissue ingrowth member is positioned in the subcutaneous tissue; (xi) removing the tubular guide member; and (xii) closing the first opening with a suture whereby the permanent catheter (a) is no longer exposed through the first opening, (b) extends for at least several centimeters under the patient's skin between the second opening and the location where the permanent catheter enters the blood vessel, and (c) extends out of the second opening so that a proximal end of the permanent catheter is located outside of the patient's body.
In contrast to the direct puncture catheter technique, the tunneled catheter technique results in the placement of a catheter in a patient's body in a manner which allows the catheter to remain more safely in the patient's body for a relatively long period of time. For example, a degree of safety is achieved by separating the following two openings by at least several centimeters: (i) the skin opening through which the catheter enters the patient's body, and (ii) the blood vessel opening through which the catheter enters the patient's vascular system. This safety feature increases the difficulty for microbes to migrate up the length of the catheter from the skin opening and cause infection in the patient.
In addition, another degree of safety is achieved by providing a tissue ingrowth member which is attached to and extends around an outer surface of the catheter. As the catheter is left in the subcutaneous tunnel over a period of time, the tissue ingrowth member becomes affixed to the subcutaneous tissue of the patient's body thereby providing a secure attachment of the catheter to the patient's body. Providing a secure attachment between the catheter and the patient's body reduces the likelihood that the catheter will be inadvertently removed or withdrawn from the patient's body. Moreover, since the subcutaneous tissue becomes attached to the tissue ingrowth member, a physical barrier is created between following two openings: (i) the skin opening through which the catheter enters the patient's body, and (ii) the blood vessel opening through which the catheter enters the patient's vascular system. This physical barrier further increases the difficulty for microbes to migrate up the length of the catheter from the skin opening and cause an infection in the patient. Since the tissue ingrowth member is not positioned at the skin opening, it has no effect on microbial migration and subsequent possible infection at the proximal end of the tunnel, which could lead to the need to remove the catheter prematurely.
While the tunneled catheter technique provides the significant advantage of allowing the catheter to remain safely in the patient's body for a relatively long period of time, there are also significant disadvantages of the tunneled catheter technique. In particular, current CVC designs seriously compromise the skin's ability to protect the body from infection. CVC-related infection is a serious health problem that significantly increases the morbidity rate and cost of catheter usage. All previous attempts to modify tunneled CVC designs to reduce infection have failed to significantly decrease this cost or the morbidity rate. The primary reason for the failure of conventional CVCs is that none of the modified versions effectively block the path of microorganisms through the skin and into the body. See, for example, C. Crosby et al., “Skin Antisepsis: Past, Present, and Future,” JVAD (Journal of Vascular Access Devices) (Spring 2001), which article is incorporated herein by reference.
As discussed above, it has been recognized in certain classes of medical catheter devices, for instance peritoneal dialysis catheters, that promoting epidermal tissue growth around a cuff or lip of the device can provide advantages over conventional methods. This topic is well summarized in an article written by Poirier et al., published in 1986 in the periodical “Frontiers in Peritoneal Dialysis” titled “Elimination of Tunnel Infection,” which article is incorporated herein by reference. The authors teach that the epidermis is both the body's natural barrier to infection and the habitat of the largest reservoir of microorganisms causing catheter-related infection. Trauma to the epidermis, such as the incision required for insertion of catheters into the body, sets in motion a series of physiological mechanisms designed to heal the trauma and to re-establish the skin's capacity to prevent infection. Insight into these natural mechanisms, and equipping catheters with cuff technology at the incision site to facilitate the successful completion of these natural defense mechanisms, has been demonstrated to be an effective strategy to reduce catheter-related morbidity as well as cost. The uses of such natural mechanisms are summarized in the an article written by Dasse et al. in the periodical “Advances in Peritoneal Dialysis” titled “A Polyurethane Percutaneous Device for Peritoneal Dialysis,” which article is also incorporated herein by reference.
Polyester fabric, commonly referred to by its tradename Dacron™, is one biocompatible, porous bed material which has been found to encourage the growth of tissue and collagen on and around the fabric for tissue ingrowth purposes. Fabric pore size is the characteristic most often quantified to specify the fabric most suitable for a given application. Fabric thickness and surface treatment are secondary factors for selection. This subject has been discussed in many technical and clinical journals. Two such references are “The effect of fiber diameter and fiber spacing on soft tissue ingrowth into porous polyester fabrics” by Ferguson et al., and “The effect of fiber diameter and carbon coating treatment on the in vitro and in vivo cellular response to dacron fabric materials” by Hong et al., both presented at the 17th Annual Meeting for the Society for Biomaterials held in May of 1991, both of which published papers are incorporated herein by reference. Another good reference on this subject is “Tissue reaction to Dacron velour and titanium fibre mesh used for anchorage of percutaneous devices” by Paquay et al. published in 1996 in Volume 17 of the periodical “Biomaterials,” which article is also incorporated herein by reference.
The tissue ingrowth cuff designs developed for peritoneal dialysis catheters, however, cannot be readily translated to tunneled CVCs. Unlike peritoneal catheters, tunneled CVCs need to have their tips placed in a very specific location, typically the Superior Vena Cava/Right Atrial Junction (SVC/RA), in order to function properly over many months. Interventional radiologists are acutely aware of the need for highly precise tip placement because they are most frequently called on to resolve CVC complications. See, for example, “Tip Location of Peripherally Inserted Central Catheters,” JVAD (Summer 1998), which article is incorporated herein by reference. The clinical benefits of proper catheter tip placement are very clearly spelled out in the DOQI standards issued in 1998 for proper placement of hemodialysis catheters. With currently available technology, the ability to precisely position CVC tips in the SVC/RA is enabled largely by the freedom to adjust/position the cuff location anywhere within the subcutaneous tunnel length. Thus, current tunneled CVC products cannot use cuffs that need to be precisely located at the incision site without losing the flexibility needed to ensure that the catheter tip is positioned precisely at the desired internal body location. This fundamental design conflict has led those skilled in this art to conclude that it is not feasible to combine conventional tunneled CVCs with the fixed implantable cuff technology, such as those described in U.S. Pat. No. 5,662,616 (Bousquet). This problem has heretofore been neither anticipated nor in any way addressed by the literature or practice in this art.
It has now been found, however, that a CVC apparatus which includes an adjustable epidermal tissue ingrowth cuff assembly according to the present invention overcomes these problems and deficiencies of the prior art CVC devices. Specifically, the apparatus and methods of the present invention allow a physician to place a fixed epidermal tissue ingrowth cuff assembly within a skin incision site and, subsequently, to adjust the location of the distal (internal) tip of a catheter assembly associated with the tissue ingrowth cuff assembly to precisely position the catheter tip at the desired body site without disturbing, moving, or stressing the fixed tissue ingrowth cuff.